Global sea-rise levels by 2100 maybe lower than predicted

Washington, September 5 : A new study has determined that global sea-rise levels by 2100 maybe lower than some scientists have predicted.

The study, carried out by researchers at the University of Colorado at Boulder, US, has concluded that despite projections by some scientists of global seas rising by 20 feet or more by the end of this century as a result of warming, even a rise of much more than 6 feet is a near physical impossibility.

Tad Pfeffer, a fellow of CU-Boulder's Institute of Arctic and Alpine Research and his colleagues, made calculations using conservative, medium and extreme glaciological assumptions for sea rise expected from Greenland, Antarctica and the world's smaller glaciers and ice caps - the three primary contributors to sea rise.

The team concluded that the most plausible scenario, when factoring in thermal expansion due to warming waters, will lead to a total sea level rise of roughly 3 to 6 feet by 2100.

According to the research team, "We consider glaciological conditions required for large sea level rise to occur by 2100 and conclude increases of 2 meters are physically untenable."

"We find that a total sea level rise of about 2 meters by 2100 could occur under physically possible glaciological conditions, but only if all variables are quickly accelerated to extremely high limits," he added.

"The gist of the study is that very simple, physical considerations show that some of the very large predictions of sea level rise are unlikely, because there is simply no way to move the ice or the water into the ocean that fast," said Pfeffer.

The team began the study by postulating future sea level rise at about 2 meters by 2100 produced only by Greenland.

Since rapid, unstable ice discharge into the ocean is restricted to Greenland glacier beds based below sea level, they identified and mapped all of the so-called outlet glacier "gates" on Greenland's perimeter - bedrock bottlenecks most tightly constraining ice and water discharge.

"For Greenland alone to raise sea level by two meters by 2100, all of the outlet glaciers involved would need to move more than three times faster than the fastest outlet glaciers ever observed, or more than 70 times faster than they presently move," said Pfeffer.

"And they would have to start moving that fast today, not 10 years from now. It is a simple argument with no fancy physics," he added.

"In my opinion, some of the research out there calling for 20 or 30 feet of sea rise by the end of the century is not backed up by solid glaciological evidence," he further added.